Patients taking DOACs for atrial fibrillation could enjoy added protection against dementia when compared to warfarin, a UK study has shown.
The real-world study, which followed 39,200 first-time oral anticoagulant users with non-valvular AF, found those on DOACs were 16% less likely to have dementia (adjusted hazard ratio [HR]: 0.84) and had a 26% reduction in incident mild cognitive impairment (aHR: 0.74) versus patients on vitamin K antagonists (VKA).
Overall, 1,258 patients had a dementia diagnosis recorded between 2012 and 2018, with a resulting incidence rate of 16.5 per 1,000 person-years.
While clinical trials could add weight to these findings, it “may be relevant to consider cognitive risk profile when prescribing oral anticoagulants for AF to older individuals”, London School of Hygiene & Tropical Medicine Epidemiologist Dr Sharon Cadogan and her team wrote in Heart.
AF can increase stroke risk five-fold and double dementia risk, with stroke, silent cerebral infarction and microemboli, as well as indirect effects of cerebrovascular hypoperfusion on oxidative stress, inflammation and blood-brain barrier disruption likely contributing to vascular dementia and Alzheimer’s disease, they wrote.
DOACs’ “notable effectiveness against stroke” may therefore be key to their dementia-stalling effect, the authors suggested.
Given these findings, University of Birmingham cardiovascular researcher Dr Winnie Chua said more needs to be done to improve oral anticoagulant, and particularly DOAC, adherence.
In an accompanying editorial, Dr Chua said one-year DOAC adherence rates were around 61%, 72% and 79% for dabigatran, rivaroxaban and apixaban, respectively, and 63% for VKAs.
“These suboptimal rates are a cause for concern, even more so if the [oral anticoagulants] also play a role in preventing cognitive decline and dementia,” she wrote.
Extending the roles of health psychologists and implementation scientists to “uncover behavioural drivers and motivators of adherence”, and working with patients to improve messaging around the importance of oral anticoagulants could lead to better persistence campaigns and reduce the burden of conventional education and monitoring approaches on healthcare personnel, she suggested.
Dr Chua also flagged that, while Dr Cadogan’s results were positive, sensitive cognitive test batteries or biomarkers are needed to detect neurological disease progression in AF patients who aren’t DOAC candidates or are experiencing neurological conditions despite optimal therapy.
Ultimately, however, she said it’s clear that DOAC use is “not only associated with decline in AF-related stroke” and better resource and cost efficiencies, it has a seemingly positive impact on dementia diagnoses in AF patients.
“These indications of additional cognitive protection should ease the decision-making process for initiation of oral anticoagulation with DOACs, and we eagerly await outcomes of prospective studies in this area.”
“As there is no cure for dementia, our best bet lies in early identification and early intervention to prevent non-reversible changes,” she concluded.